1. Field of the Invention
The invention generally relates to locking mechanisms for the canopies of aircraft, and more particularly to an improved, economic, and simplified lock for the so-called "clamshell" canopy which provides for a positive locking of the canopy, while yet being readily operable from both inside and outside the cockpit in order to release the canopy for opening displacement, even under emergency conditions.
2. Description of the Prior Art
As can be fully appreciated by those familiar with the aircraft industry, particularly aircraft equipped with pivotal canopies, there appears to be a myriad of locking devices available for securing such canopies in place. As is also appreciated, however, by those familiar with the aircraft industry, efforts are continuously being made to simplify canopy locks for thus reducing weight and complexity, without subjecting pilots to numerous hazardous conditions which may result from oversimplification. For example, where a manually operable handle is employed, for controlling a canopy lock, it is necessary that access to the handle be afforded from outside the aircraft as well as from inside the cockpit, where unimpeded emergency rescue operations can be conducted.
Additionally, any handle for a release mechanism located within the cockpit must be capable of affording a positive locking operation which normally cannot be interrupted through inadvertent, or accidental engagement of a pilot's hand, arm, shoulder, knee, or the like, particularly while the aircraft is in flight.
As a consequence of the various requirements for increased simplicity and reliability, as well as the presence of an overriding interest in production and maintenance costs imposed on designers of aircraft and locking mechanisms commonly provided for aircraft canopies, there is a continuing need to provide improved locks.
During the course of a preliminary search conducted on the instant invention, the patents listed on the enclosed Form PTO-1449 were discovered.
While the concept of employing a detent lock adapted to be actuated from one side of a door, or the like, by a push-button, as well as the concept of employing a detent lock adapted to be actuated from the same side of a door by a pull-pin, generally is not new, it is believed that none of the references discovered during the course of the search suggest a canopy lock for a clamshell canopy, such as the lock hereinafter more specifically described and claimed.
For example, the patent to McCaffrey U.S. Pat. No. 311,134 discloses a door retainer having a mechanism similar to that of a push-button and a detent in which a button, exterior to the door, is employed to drive a spring-loaded bolt out of engagement with a recess. However, there is no provision for actuating the bolt from within the door.
The patent to Griswold, Jr. U.S. Pat. No. 3,171,644 discloses a pull-button for pulling a detent pin from a ramp-shaped recess. The button and detent are mounted in the distal end of an automobile window crank; however there is neither an interior window crank nor an interior device for actuating the detent pin.
The remaining references were selected on the basis of a general representation of the state of the art.
It is therefore the general purpose of the instant invention to provide an improved canopy lock which is simple and economic to fabricate, install, operate and maintain, and yet being capable of providing a positive-locking function for a clamshell canopy.